Energy system

ABSTRACT

Storage of excess energy on a domestic or small scale as a result of input feeds from solar panels and like can be problematic. Furthermore ensuring such panels operate at best temperatures can be difficult by operating through a controller a heat pump and such panels or other sources of energy such as anaerobic digesters excess heat can be stored in a ground mass below the system for use in maintaining heating as well as operation of the panels at best temperatures.

This invention relates generally to energy systems and particularly energy systems for energy conservation and efficiency.

It is known to provide photovoltaic panels, air source heat pumps, earth source heat pumps and solar thermal panels to varying degrees in order to provide efficient use of energy and increase uses of renewable energy sources. Significant problems particularly with variable and seasonal energy sources such as PV panels, solar thermal panels and solar thermal panels relate to the fact that it is difficult to store energy for extended periods and for convenient retrieval of that energy. Furthermore periods of maximum energy collection may not coincide with periods of maximum energy usage.

Schemes can be provided for macro generation systems such as pumping water into hydroelectric power reservoirs during periods of excess power capacity but these are not suitable for smaller district or domestic situations. What is needed is a means to combine energy sources and usage in to a common mono energy core within a combined energy system.

In accordance with aspects of the present invention there is provided an energy system for a building, structure or similar, the system comprising an upstanding solar panel spaced from an adjacent wall surface to define a channel coupled at an upper end to a heat exchanger whereby a fluid such as air naturally raises in the channel to the heat exchanger, the heat exchanger connected to a fluid circuit extending to at least one sub-terrain loop below a bottom ground level to a depth within a sub-terrain mass such as earth thereabout and configurable whereby heat is retained within the mass thereabout by heating the mass when a fluid flow is above a pre-determined temperature to provide temperature modulation of a fluid in the fluid circuit return to the heat exchanger at least towards a desired fluid temperature for operation of the heat exchanger.

The heat exchanger may act as or have a part which is a heat pump.

The solar panel may be a photovoltaic panel. The solar panel may be a solar thermal panel. Advantageously the solar panel may be a combined solar photovoltaic and thermal panel. The solar panel may be formed by a plurality of tile or plates assembled edge to edge. The solar panel may be substantially vertical. Where the solar panel provides a solar thermal function a labyrinth flow path may be provide for a coolant flow. The labyrinth may of variable density within the panel. Generally the labyrinth may be denser towards the top of the panel whereby greater heat energy is removed.

The channel may have a fixed consistent spacing from the surface along the length of the panel. The channel may have a fixed variable spacing from the wall surface along the length of the panel. The channel may have an adjustable spacing from the wall along the length of the panel. Sections of the panel may be displaceable independently from the remained of the panel. Sections of the panel may be hinged along one edge whereby an opposite edge may be displace outwardly to draw adjacent air into the channel and/or inwardly into the channel so air flow in the channel can escape the channel. The channel may include features to regulate fluid flow and/or heat exchange between the rear of the panel or wall and the fluid flow within the channel. The features may include baffles, ribs, grooves, studs and struts. The channel may include a damper to regulate the rate of fluid flow through the channel. The damper may act across the whole width of the channel or several dampers or shutters may be provided with each damper or shutter arranged to act in a portion or section of the channel. The channel may be substantially open at a bottom end. The channel may be wider at the bottom end compared to the top end to naturally draw fluid flow within the channel upwards. The channel may be associated with a controller and appropriate actuators whereby the temperature of the panel is regulated to a specified desired temperature. The desired temperature may be that specified for optimum operation of the panel. The controller may be associated with a temperature sensor. The controller may be associated with an electrical current flow sensor or ammeter whereby the controller thorough the actuators will adjust the channel for optimum operation of the solar panel dependent upon the specified desired temperature or not so allowing for aging and manufacturing variations in the panel as well as temperature variation from that specified by a manufacturer for optimum operation.

The heat exchanger may be coupled to a buffer heat store for a heating system. The heating system may provide direct heating to units. The heating system may provide exchange heat to a hot water system to units. There may be a plurality of units. Each unit may have an individual regulator for heat taken from the buffer heat store.

The fluid circuit may include a manifold. The fluid circuit may include a plurality of pipes in circuit pairs to a sub-terrain loop. The circuit pairs may be coupled to the manifold. The circuit pairs and respective sub-terrain loop may form a matrix extending laterally below the channel. The pipes forming part of the fluid circuit may have individual valves or groups of pipes may be grouped with a valve for the group of pipes. The pipes may have a substantially consistent cross-sectional area or have different cross-sectional areas dependent upon position and in particular lateral placement relative to the channel. The pipes may include chokes to regulated fluid flow. Pipes or bore holes about at sub-terrain loop and upward may be packed with insulation material to at least choke or inhibit lateral heat loss beyond the mass. Thermal insulation may be provided above the sub-terrain loop and/or the manifold. The insulation may be porous.

Means may be provided to determine moisture content in the sub-terrain mass whereby a determination of heat transfer capacity and/or heat retention capacity of the sub-terrain mass may be determined. The means may be associated with a controller to adjust the fluid temperature and/or fluid flow rate in the fluid circuit may be adjusted dependent upon moisture content in the mass.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

FIG. 1 is a schematic illustration of an energy system in accordance with aspects of the present invention;

FIG. 2 provides schematic cross-sectional illustrations a) to c) of various features of a channel formed between a solar panel and a wall in accordance with aspects of the present invention; and,

FIG. 3 provides schematic cross-sectional illustrations a) to c) of various features of a sub terrain loop associated with a fluid circuit of an energy system in accordance with aspects of the present invention.

It will be understood that integrated and mono energy systems which take a holistic approach to consideration of its parts can lead to improved efficiency and energy conservation. It is known that photovoltaic (PV) panels particularly if appropriately located can provide significant levels of electrical energy generation. Similarly solar thermal panels can use heat from the Sun to warm water to relatively high temperatures so that a heat exchanger can harness that heat energy. Furthermore air source heat pumps and ground (earth) source heat pumps are known to provide an energy source. The difficulty with solar panels whether they are PV or solar thermal or a combination is that new heat energy is not available at night, the panels can over heat or is too cool to operate at their optimum condition and ground earth heat pumps are consistent but of a nascent fixed response. Aspects of the present invention aim to provide a more efficient energy system by combining the features of solar panels and air/ground heat pumps.

One aspect of the present invention relates to improving operation of solar panels. These panels generally will be specified to provide optimum or at least a known performance at a desired temperature at least upon initial manufacture. Whether optimum or known a designer of an energy system including solar panels particularly PV panels will use this information in their design criteria to meet the project specification for each installation.

However, panels will rarely operate for long at such a temperature with variations throughout a day, during different Seasons and with aging of the panel. There will also be some variation with manufacturing tolerances and ‘dusting’ etc. of the surface of panel. By one aspect of the present invention a solar panel is presented in a substantially upright/vertical orientation or at least at an angle to allow an up draft in a channel formed by having the solar panel offset or spaced from a wall or surface such as that of a building or similar structure although it may also be possible to have the panel offset relative to a slope on a hill side but then it may be necessary to provide a wall or surface or screen which is graded so the spacing of the channel can be set for control.

The channel behind the solar panel allows a fluid flow which is normally air to cool the panel as required or at least nearer to the desired temperature for optimum or known operation of the panel. As will be described later the configuration of the channel can be set or adjusted as required but essentially the fluid or air flow is heated in the channel and this flow is presented at an upper end of the channel to a heat exchanger which acts as an air source heat pump to provide hot fluid for storage in a buffer heat store but also in accordance with aspects of the present invention excess heat is presented from the heat exchanger via a heat pump part to a fluid circuit leading to a sub-terrain loop or loops.

The sub terrain loop will be at a sufficient depth that when there is excess heat this will be transferred to a sub terrain mass about the loop but otherwise heat will be inter-exchanged to the fluid in the fluid circuit to modulate the fluid in terms of temperature. Normally several sub terrain loops will be provided in a matrix or pattern with equal spacing or a distribution to provide a desired heat response and retention capacity in the mass about them. It will be appreciated that there is a general consistency but also some deviations in the capacity of the sub terrain mass due to soil type, rock type and moisture content so the actual loop distribution as well as cross-section of the pipes forming the loops and matrix for particular installations may be different.

FIG. 1 provides a schematic overall illustration of an energy system 1 in accordance with several aspects of the present invention including as described above the aspect relating to provision of a channel 2 to provide hot air 3 flow to a heat exchanger 4 used with and as part of a heat pump 8 assembly and to regulate the temperature of a solar panel 5 spaced from a wall 6 of a building or surface of a suitable structure which may include accommodation or other units 7. In accordance with another aspect of the present invention the heat pump 8 is connected to a fluid circuit 9 which extends to sub terrain loops 10 below a ground level 11 upon which the structure and so wall 6 is located. The solar panel 5 and heat pump 8 are used to heat the units 7 through a buffer heat store 12 and a hot water supply tank 13 through an appropriate flow path 14 to each unit 7 in a circuit. If PV the solar panels will also provide electricity.

The solar panel 5 is offset and spaced from the wall 6 with normally a layer 15 of insulation also provided to deduce heat losses or gains by the building as required. The hot air flow 3 rises so that at a bottom end 3 a the air is coolest whilst at 3 b the air is warmer and at 3 c the air is hottest. It will be understood that the air movement is natural and nascent in that hot air rises but generally a valve 16 into the heat exchanger 4 is provided to control hot air flow 3 and particularly effective lag within the channel 2 which in turn will affect the temperature of the presented air 3 to the exchanger 4. It will be understood that other fluids to air may be used but such fluids will inevitably need to be captured in a circuit path so may not be as convenient. With air 3 an open bottom or lower end 17 is provided to the channel 2 so that hot air 3 c is present at an upper or top end about the valve 16 of the channel 2 by natural convection.

As indicated above the solar panel 5 may be a PV panel or a solar thermal panel or a combination of such PV and solar thermal panels either one on top of the other or in a mosaic of panel sections side by side with edges abutting each other. It will be understood that energy systems in accordance with aspects of the present invention will tend to be associated with buildings so the panel 5 will be made up of a number of tiles or plates assembled together to form the solar panel 5. The panel 5 will be substantially vertical or upright to allow a natural convection up draft although a steep angle may also be allowable dependent upon operational conditions.

The hot air 3 is used in the heat exchanger 4 but also act to regulate the temperature of the solar panel 5. It will be understood that solar panels and particularly PV solar panels are specified for operation at a specific temperature such as 25 C so although the PV panel will still operate at other temperatures the performance may be different making difficulties for a designer and for optimising system operation. The fluid movement in the channel 2 will cool the panel 5 dependent upon flow rate, initial temperature etc. In order to regulate the air or fluid flow in the channel 5 a number of features may be provided individually or collectively. It will also be understood that where the solar panel 5 includes a solar thermal feature that a labyrinth path (not shown) embedded with the panel 5 for the working fluid flow can be used to cool the panel 5. The intensity or density of the labyrinth flow path may vary in different sections of the panel 5 again to provide different levels of heat absorption in to the working fluid and so again temperature regulation of an associated section of the panel to control operational temperature of the panel 5. Typically the labyrinth will be denser towards the top of the channel to provide more heat transfer removal and cooling of this part of the panel 5.

The channel 2 may have a fixed gap or spacing which is consistent along the length of the panel 5 adjacent the wall 6 or which varies as desired along the length of the channel to stimulate or regulate hot air 3 flow within the channel 2. As an alternative but then necessitating an actuation mechanism the channel 2 may be adjustable in terms of width or cross-sectional area to varying air flow 3 dependent upon prevailing environmental conditions. Such variation will require sections or parts of the panel 3 to be moveable as required. If as illustrated in FIG. 2 (a) a part 25 of the panel is hinged on one edge then as shown with regard to a part 25 a there may be movement of an opposite edge outwards from the wall 26 so that air can be drawn into the hot air flow 22 with a channel 22. If a part 25 b is moved inwards towards the wall 26 then some of the air flow 23 may be diverted out of the channel 22.

Features to regulate and control hot air flow 3 as illustrated can be used with the channel in addition to control valves 16 to the heat exchanger 4. As illustrated in FIG. 2(b) a channel 32 is defined between a panel 35 and a wall 36 with an insulation layer 30 shaped to provide a narrowing of the channel for flow control. An insulation layer 30 or a solar panel 45 or possibly a wall 46 could include features such as illustrated in FIG. 2(c) such as baffles 100, spikes 101, studs 102, ribs 103, struts 104, bumps 105 and patches 106 on panel plates or across junctions between plate/tiles forming the solar panel to disrupt and regulate flow for near surface flow turbulence and heat transfer to the air as a working hot fluid for presentation to the heat exchanger 4 (FIG. 1). A further feature which may be provided is a damper 200 which can be deployed across a channel 62 between a solar panel 55 and a wall 26/insulation layer 50. The damper 200 can be hinged and variably displaced to control hot air flow using an associated actuator controlled by a controller.

A controller will be associated with sensors to control operation of the energy system dependent upon current or long term objectives. It will be understood that a respective temperature sensor can be used with regard to the solar panel, the hot air flow, the fluid flow in the heat exchanger 4, the heat pump 8, the buffer store 12, the hot water store 13, in the fluid flow circuit 9 and in the sub terrain loop or loops dependent upon how sophisticated the control regime is for operation of the energy system. Essentially a control strategy will be determined for each type of installation so that feedback control is achieved by adjusting hot air flow in the channel 2, setting valves for transfer flows between the heat exchanger/heat pumps and in the fluid circuit 9.

Another form of sensor may relate to electrical current or an ammeter so that rather than providing a temperature objective the controller may act to seek or hunt for best operational PV performance. As indicated above solar panel manufacturers will specify a desired operational temperature but due to aging, conditioning of the panel, manufacturing tolerances and other factors this may mean that optimum electrical power generation may occur at different solar panel temperatures at different times. By controlling the cooling effect of the hot air flow in the channel an optimum operating condition can be determined and it will also be understood that some of the stored heat energy in the energy system may be ‘re-injected’ into the channel 2 by appropriate piping to warm the solar panel if that will increase PV electrical energy generation.

It will be appreciated most long term heat energy storage will be in the sub terrain loops 10 and adjacent sub terrain mass 201 but it will also be understood for more immediate usage the buffer energy store 12 and the hot water tank 13 are provided to supply the units 7 through a circuit 14. Generally the heat pump 8 through a controller will prioritise maintaining necessary conditions in the store 12 and hot water tank 13 in preference to long term heat energy storage in the loops 10/incident sub terrain mass 201. Thus, only excess heat energy will be stored in the loops 10/mass 201 when available at certain times of the day and most notably more energy will tend to be stored in the summer in comparison with the winter so providing some seasonal storage within the energy system.

The fluid circuit 9 will be formed of pipes with a down flow side 9 a to and a return flow 9 b from a manifold 200 to ensure even and balanced fluid flow into respective bore holes generally lined with a bore pipe to the sub terrain loops 10 (FIG. 1). In FIG. 1 it will be understood that the loops 10 will be well below the ground level 11 (greater than 6 metres and to a depth of 20 metres or so) upon which the structure and so the wall 6 is located.

About the loops 10 it will be understood that a sub terrain mass 201 will be provided formed of soil, rock and moisture it is in this mass 201 that excess heat energy will be stored. Although a single sub terrain loop 10 may be provided it will be understood this will have limited heat storage capacity in the mass 201 about the loop 10 so generally a plurality of loops 10 will be provided.

The loops 10 will be arranged in a distribution and pattern which may have even spacing or not but with the objective of providing heat energy storage in the mass 201. It will be understood that each sub terrain mass 201 will have different characteristics which contribute to its heat retaining capacity and thermal losses. In such circumstances the sub terrain loop 10 patterns and distribution will be specified for each installation. In order to reduce or choke radial heat losses insulation bore holes 202 may be drilled about the loops 10 in close order and these bore holes 202 may be filed with a thermal insulation material. The insulation material may be porous so that natural aquifers are not unduly blocked or inhibited. Nevertheless it will be appreciated that the moisture content within the sub terrain mass 201 is important as water will probably significantly add to the heat transfer capacity and rate of the mass 201 so retaining moisture in some circumstances may be beneficial.

Each loop 10 as indicated is connected to a manifold 200 at least on the return side of the fluid circuit 9 so that the returned fluid to the heat pump 8 is effectively from the whole long term store provided by the loops 10. Each return junction for the loops 10 to the manifold 200 will typically have a valve 203 so that the respective loop 10 can be isolated if there is a problem with leakage/failure or to control use for blending or so that flow in one or more loops can be stop whereby the fluid then remains in the loop to be heated or to give heat to the mass 201 thereabout for storage.

As indicated above a manifold 200 will typically be provided and this will at least operate on the return side to ameliorate the return flow pressure and temperature to the heat pump from the fluid flow circuit. An inlet or down flow side 9 a of the fluid flow circuit could also have a manifold but with probably less effect than a flow valve switching regime where fluid flow with excess heat from the heat pump 8 is switched with the valves between individual or groups of circuit pairs to sub terrain loops 10 in a sequence. In such a regime the respective valve 203 will be opened so that the new hot fluid flow will ‘push’ the stored fluid in the loop 10 out into the manifold whilst the new flow from the fluid circuit 9 a will replace it for heat energy storage in the sub terrain mass 201.

As can be seen the fluid circuit 9 will generally have one down pipe 9 a and one return pipe 9 b. Hot fluid flow as a result of excess heat at the heat pump 8 will pass down the down pipe 9 a typically with a gravity effect from an elevated position along with syphoning effects so that only relatively modest additional pumping will be needed. Each slug or aliquot of hot excess heat energy fluid will pass into a circuit pair with a sub terrain loop 10 in sequence for energy storage. It will be appreciated that a controller will determine the sequence using the valves 203 and switch valves (not shown) for each circuit pair for a loop 10. There will be a number of circuits and loops 10 but once all are ‘charged’ with hot fluid and after an appropriate period of linger for heat transfer to the matrix 201 it will be necessary to open the valves 203 in sequence to release the now cooler fluid into the manifold 200. By such an approach the mass 201 can be heated to store excess heat energy within its capacity when available whilst when there is a heat deficit or heat energy to the heat pump 8 as an air source heat pump using the hot air 3 in the channel 2 via a working fluid flow form the exchanger 4 is insufficient then heat energy can be taken from that stored in the mass 201. Clearly heat energy stored in the mass is by effectively elevating the natural heat level by a few degrees Kelvin at that strata in the ground and this elevation will not be everlasting but will be sufficient to improve the efficiency of the heat pump 8 when acting as a ground source heat pump in the building or other structure associated with the energy system.

It will be noted that the fluid circuit 9, the manifold 200 and fluid circuits to the loops 10 are generally below the building within which the energy system is provided. In such circumstances the building itself will provide some insulation to these energy storage parts of the energy system and any losses will effectively leak into the building to warm it in any event. Nevertheless as illustrated schematically in FIG. 3(a) a manifold 300 can be readily arranged with a layer 301 of insulation material around it. In FIG. 3(a) it will be noted that the fluid circuits 302 are of different lengths which may be beneficial in some circumstances and initial parts of the down and return pipes of the circuits could be lagged with insulation material 304 as heat losses nearer the ground level 11 (FIG. 1) may be higher than at the operational depth of the ends of the loops 302 used for heat energy storage.

It will be appreciated that some structures may be located upon strata of hard rock relatively near to the surface so that it may be difficult to accommodate the number of fluid circuits and sub terrain loop as desired or there may just be design or other operational opportunities. In such circumstances as illustrated in FIG. 3(b) again fluid circuits with sub terrain loops 502 are provide of varying configuration but particularly extending more laterally of a manifold 500 so that flow length in the circuits and particularly the loops 502 at effective depths can be achieved above a hard rock strata 503 which may be difficult and/or expensive to drill for bore holes and piping for the fluid circuits to the necessary sub terrain loops.

There may be situations where a large diameter mole boring machine or even tunneling machine may be used to provide a hole which may be lined with concrete rings to create a hole to a desired depth. In such circumstances as illustrated in FIG. 3(c) a lined hole 400 may be created then a pre-formed manifold 401 with fluid circuits 402 to sub terrain loops 403 in a sub terrain mass 404. In such circumstances the mass 404 can be optimised for heat storage and transfer to the loops/fluid circuits and the pipe work optimised in terms of shapes and surface ribs etc. for heat transfer as compared to bored pipes with earlier embodiments.

The sub-terrain loops and fluid circuits can be operable individually or in groups as described previously with appropriate valve combinations. It will also be understood that the valves 203 can be used to regulate a minimum trickle flow or increase flow as required by operational conditions for heat storage lag in the sub terrain mass. The pipes and tubes forming the fluid circuits can have a consistent cross-sectional area or width and may be circular or oval or otherwise shaped for performance. The pipes in a network below a manifold may have different cross-sectional areas and widths and shapes dependent upon position within the network or matrix located in the sub-terrain mass. In some circumstance rather than using different configurations of pipe it may be desirable to use a standard available pipe with insert chokes to give different performance at different parts of the matrix.

It will be appreciated that the moisture content of the sub terrain mass is important with regard to its heat transfer capability and the heat retention capacity of the sub terrain mass. In such circumstances a sensor can be provided to determine the current moisture level in the mass in order that a controller can adjust fluid flow rates into the sub terrain loops for heat transfer in terms of linger of the fluid in the pipes for storage of excess heat energy or retrieval as required to supplement that available to the heat pump though the air source from the channel 2 (FIG. 1).

As indicated above generally the present invention will be used with variable or seasonal energy sources such as PV panels, solar thermal panels, wind turbines and the like but it will also be understood that other sources of energy are available such as anaerobic digesters which may have a greater generation power upwards of 20 kW so that some of this energy may also be stored in accordance with aspects of the present invention. It will also be understood if it would help with efficiency that a conventional generator operation at a steady and consistent load could have excess power not required at times stored within the energy system of aspects of the present invention. Similarly, at times of low tariff or cost electricity on a supply grid some of that electrical energy could be stored when available with an appropriate switch.

It will be understood that the energy storage and rate of heat energy exchange capacity of the sub-terrain mass in most cases will depend upon its moisture content. The fluid circuits in accordance with aspects of the present invention will generally be located to a reasonable depth where the moisture content is relatively constant but even so the upper parts of the circuits will pass through sections of more variable moisture content. In such circumstances means may be provided to alter or regulate the moisture content to maintain good energy storage capacity and heat transfer rates. It will also be understood that there may be natural or man-made pools of water such as a result of previous mining which can be used as a sub-terrain mass for energy storage. However, care must be taken that the water is contained and does not flow as an aquifer as this will not contain the energy for recovery.

It will be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein. 

1. An energy system for a building, structure or similar, the system comprising an upstanding solar panel spaced from an adjacent wall surface to define a channel coupled at an upper end to a heat exchanger whereby a fluid such as air naturally raises in the channel to the heat exchanger, the heat exchanger connected to a fluid circuit extending to at least one sub-terrain loop below a bottom ground level to a depth within a sub-terrain mass such as earth thereabout and configurable whereby heat is retained within the mass thereabout by heating the mass when a fluid flow is above a pre-determined temperature to provide temperature modulation of a fluid in the fluid circuit return to the heat exchanger at least towards a desired fluid temperature for operation of the heat exchanger. 2-5. (canceled)
 6. A system as claimed in claim 1 wherein the solar panel provides a solar thermal function by a labyrinth flow path for a coolant flow and the labyrinth has a variable density within the panel.
 7. (canceled)
 8. A system as claimed in claim 6 wherein the labyrinth is denser towards the top of the panel whereby greater heat energy is removed.
 9. A system as claimed in claim 1 wherein the channel has a fixed consistent spacing from the surface along the length of the panel.
 10. A system as claimed in 1 wherein the channel has a fixed variable spacing from the wall surface along the length of the panel.
 11. A system as claimed in 1 wherein the channel has an adjustable spacing from the wall along the length of the panel.
 12. A system as claimed in claim 1 wherein sections of the panel are displaceable independently from the remainder of the panel.
 13. A system as claimed in claim 1 wherein sections of the panel are hinged along one edge whereby an opposite edge is displace outwardly to draw adjacent air into the channel and/or inwardly into the channel so air flow in the channel can escape the channel.
 14. A system as claimed in claim 1 wherein the channel includes features to regulate fluid flow and/or heat exchange between the rear of the panel or wall and the fluid flow within the channel and the features include baffles, ribs, grooves, studs and struts. combined with 15
 15. (canceled)
 16. A system as claimed in claim 1 wherein the channel includes a damper to regulate the rate of fluid flow through the channel and the damper acts across the whole width of the channel or several dampers or shutters are provided with each damper or shutter arranged to act in a portion or section of the channel.
 17. (canceled)
 18. A system as claimed in claim 1 wherein the channel is substantially open at a bottom end.
 19. A system as claimed in claim 1 wherein the channel is wider at the bottom end compared to the top end to naturally draw fluid flow within the channel upwards.
 20. A system as claimed in claim 1 wherein the channel is associated with a controller and appropriate actuators whereby the temperature of the panel is regulated to a specified desired temperature and controller is associated with an electrical current flow sensor or ammeter whereby the controller thorough the actuators will adjust the channel for optimum operation of the solar panel dependent upon a specified desired temperature or not. 20 and 23 combined
 21. (canceled)
 22. (canceled)
 23. (canceled)
 24. A system as claimed in claim 1 wherein the heat exchanger is coupled to a buffer heat store for a heating system. 25-29. (canceled)
 30. A system as claimed in claim 1 wherein the fluid circuit includes a plurality of pipes in circuit pairs to a sub-terrain loop.
 31. (canceled)
 32. A system as claimed in claim 30 wherein the circuit pairs and respective sub-terrain loop form a matrix extending laterally below the channel.
 33. A system as claimed in claim 30 wherein the pipes forming part of the fluid circuit have individual valves or groups of pipes are grouped with a valve for the group of pipes.
 34. A system as claimed in claim 30 wherein the pipes have a substantially consistent cross-sectional area or have different cross-sectional areas dependent upon position and in particular lateral placement relative to the channel.
 35. A system as claimed in claim 30 wherein the pipes include chokes to regulate fluid flow.
 36. A system as claimed in claim 1 wherein pipes or bore holes about at sub-terrain loop and upward are packed with insulation material to inhibit lateral heat loss beyond the mass and wherein thermal insulation is provided above the sub-terrain loop and/or the manifold. 36 and 37 combined 37-38. (canceled)
 39. A system as claimed in claim 1 wherein means are provided to determine moisture content in the sub-terrain mass whereby a determination of heat transfer capacity and/or heat retention capacity of the sub-terrain mass is determined and the means provided to determine moisture content is associated with a controller to adjust the fluid temperature and/or fluid flow rate in the fluid circuit is adjusted dependent upon moisture content in the mass. 39 and 40 combined
 40. (canceled)
 41. A system as claimed in claim 1 wherein the system includes an anaerobic digester.
 42. (canceled) 